1. Field of the Invention
The present invention relates to a semiconductor device and, more particularly, a semiconductor device in which a plurality of semiconductor chips are mounted and which has a cooling mechanism for suppressing a temperature rise of a semiconductor chip.
2. Description of the Related Art
In the prior art, in order to achieve enhanced performance and downsizing of the electronic equipment, the semiconductor devices such as the multi chip module (MCM), the stacked package, and the like, each of which is constructed by mounting a plurality of semiconductor chips on the wiring substrate, have been developed.
In such semiconductor device, in order to improve the heat radiation characteristic, the semiconductor chips are cooled by fitting the radiation plate typified by the heat sink, or the fan.
As the technology related with such cooling mechanism, in Patent Literature 1 (Patent Application Publication 2001-15675), the multi chip module which is cooled by flowing the cooling water through the passage provided over the semiconductor chips is disclosed. In order to cool uniformly effectively a plurality of semiconductor chips whose heat generation characteristics are different respectively, the cooling mechanism in which a thickness of the radiation plate is changed based on an amount of heat generation of the semiconductor chips is set forth.
In the above semiconductor device, sometimes the semiconductor chips such as logic chip, ASIC, and the like, whose power consumption is large, and the semiconductor chips such as DRAM, and the like, which are weak to heat, are mounted to be mixed. Commonly, a plurality of semiconductor chips are mounted on one radiation plate such that heat can be spread to it. Therefore, the semiconductor chips having a large amount of heat generation are cooled effectively. But such heat is transferred conversely to the semiconductor chips that are weak to heat via the radiation plate, and thus a temperature of such semiconductor chips rises and a malfunction or a thermal breakdown is caused.